Alright, 2fort. I have cloak and dagger, so I find my camping corner and sit down for a while. Two engies get their stuff up in their intel. I run in, and sap as they go to attack a medic heavy uber in their courtyards. It blows up, I hide again. A pyro comes down, flames, but misses me. A single engie starts building. I wait til he's at level 2, and I stab and sap. Very gratifying. Thinking I was done, I go back to my corner. TWO pyros come down to check, and they both miss. I was very happy with my stealth and stabbing skills.
That, and my record for Backstabbing without dying is 12, which I think is pretty awesome.